The Episcopal Diocese of California is an ecclesiastical territory or diocese of the Episcopal Church in the United States of America (ECUSA) in Northern California. The founding Episcopal diocese in the state, once encompassing all of California, today the diocese comprises Alameda, Contra Costa, Marin, San Francisco, and San Mateo Counties, and the cities of Los Altos and part of Palo Alto in Santa Clara County, in the San Francisco Bay Area. The see city is San Francisco, California and the diocesan cathedral is Grace Cathedral on top of Nob Hill.